DescriptionPlanktonic larva. Young larval body oval, with somewhat pointed aboral end; body later becoming ovoid-spherical. At the moment of settling, the larval body is elongated and carries 9-11 marginal tentacles. The aboral end is then without a slime layer (that is still present higher along the body) and beset with fine hairs. The aboral pore appears between the stages with seven and nine marginal tentacles. The body colour is yellow-brown, the tentacles are somewhat darker. The marginal tentacles are cylindrical and short, almost as long as the body or shorter. The first caracteristic stage is the Antipathula, about 0.4 mm long; followed by the Cerinula stage, nearly 1 mm in length. The larvae of C. lloydii occur from January to August, with a peak during March and May. The planktonic stage is rather long: three to four months.

SizeLength generally up to 2.5 mm, maximum 4 mm.

Depth rangeSurface layer.

RemarksThe larva of Cerianthus lloydii has been described as Synarachnactis bournei (Fowler, 1897) (see Nyholm, 1944, Leloup, 1962). After the relation between the larval stages and the adult was established, the name S. bournei became a younger synonym and was therefore rejected.

Distribution in the North SeaCentral and southern North Sea, Skagerrak, Kattegat, Waddenzee.

World distributionLarvae are reported from the Channel, Irish Sea, and also (though rarely) the Mediterranean Sea (Leloup, 1962). The adult of Cerianthus lloydii is known from all European Atlantic coasts from Barentsz Sea to Gulf of Biscay.